I would say that 277/480 or 347/600 should be considered only if:

1. Distances about the farm are such that fewer on-premises utility supplied pole transformers would be needed compared with 120/240 or 120/208 volts.

Or,

2. You have a lot of equipment that takes more than 240 volts and you can get the exact voltage needed for the equipment from the power company.

Or,

3. Demand charges would be less compared with all 120/240 and/or 120/208 volt supply.

A separately metered service for the house should reduce or eliminate the need for demand metering.

When analyzing the alternatives involving stepping down from 480 or 600 volts, keep in mind that transformers are not 100% erfficient and have an "idling" aka "parasitic" current draw even when there is no load.

... cotton mill that had 600 volts ...

AC or DC? Some mills and factories dating back to the early 20'th century used 600 volts DC supplied by a power plant that also supplied trolley car systems.